The present invention relates to a cutting device of an apparatus for comminuting food products.
Cutting devices of electric motor driven comminuting apparatuses are known in the art. A known cutting device has two cutting rings which are located concentric to one another and rotate relative to one another about a common axis. The cutting rings are provided with axially extending teeth which form an annular slot therebetween. The teeth of at least one of the rings have shaped cutting members which are constituted of hard alloy or the like material.
The construction and operation of one of such cutting devices are disclosed in the German Pat. No. 3,117,439. The cutting device has a cutting ring which is mounted on a shaft of an electric motor. Cutting edges are formed between slots which are provided in a wall of the cutting ring and extend parallel to one another with inclination to the axis of the ring. This cutting ring is overlapped by a second ring which is stationarily held in a housing of the machine and has a conical wall also provided with slots forming cutting edges.
Food products which are supplied into the comminuting apparatus are sucked by the fast rotating cutting ring acting as a pump and then are flung outwardly so that they travel through the inclined slots of the driven cutting ring into the slots between the cutting edges of the second ring. During movement from the first cutting ring to the second cutting ring, the food products are finely comminuted under the shearing action of the cutting edges by pulling cut.
In this construction, an additional cutting ring is inserted from above into the outer stationary cutting ring, so that the cutting edges of the former extend into intermediate spaces of the cutter of the outer cutting rings. The width of the through-going slot in the cutting ring can be adjusted within some limits by a respective rotational position between the outer cutting ring and the additional cutting ring inserted therein.
The Austrian Pat. No. 280,832 teaches a similar comminuting apparatus. The cutting rings are constituted by a corrosion-resistant material and are provided with shaped cutting members of hard alloy or another cemented cutting material. The shaped cutting members are glued in grooves which are arranged in slot edges of the cutting rings.
When one considers the face of the outer cutting ring in accordance with this patent, which face defines an annular slot between both cutting rings, the construction can be seen to have one straight cutting edge with a relatively small cutting surface, both formed by a shaped cutting member of hard alloy. It is followed by a small radially rearwardly offset guiding surface which is formed by a tooth which carries the shaped cutting member. After this a relatively large separating gap is located in which a tooth of an additionally inserted cutting ring engages. The guiding surface of this engaging tooth follows the actual cutting gap whose width is defined by the straight cutting edge of the next following cutting element. This construction possesses some disadvantages. The width of the cutting gap cannot be determined with sufficient accuracy. It is thereby difficult to provide the degree of comminuting which is required for each particular food product. In order to maintain the cutting gap sufficiently small, it is necessary, on manufacturing grounds, to insert an additional cutting ring into the stationary outer cutting ring so that the teeth of the additional cutting ring engage between the teeth of the outer cutting ring in a comb-like manner. The manufacture of such a cutting device is therefore relatively expensive. Since the additional cutting ring must be inserted into the outer cutting ring, the latter can have only a relatively small number of teeth and thereby can carry only a small number of cutting members. This is disadvantageous in the sense of the output of the comminuting arrangement. Moreover, due to the provision of the additional ring, a separating gap is necessarily formed between the teeth of both rings. This separating gap, however, is not needed for the cutting process and results in the disadvantage that in some cases fine but relatively long-grained material falls into the finished product.
It has been recognized from practical application that erosion takes place in the region of the teeth which define the annular slot between both cutting rings and are not shielded by the hard alloy edges. This erosion considerably reduces the service life of the cutting rings.